Carbureter.



S. SHAW.

CARBUFIETER.

mmcmmu mu: DECS. x915.

Patented Mar. 5, 1918 2 SHEETS-SHEET l.

S. SHAW.

CABBUHETER wmcmlon FILED 020.6.1915.

1,258, 1 53 Patented Mar. 5, 1918 2 SHEEYS-SHEET 2.

, useful Inigirovements in .mary air inlet to y con STILLMAJM SHAW, 0FNATICK, MASSACHUSETTS,

ASSIGNOR TO MU LTIUNE CARBURETOR COMPANY, A CORPURATION 01* MAINE.

QABBURETER.

Application filed December 6, 1915.

To an 1U/L077Z it may concern Be it known that I, STILLMAN SHAW, acitizen of the United States, and resident of Natick, in the count I ofMiddlcsex and State of Massachusetts, ave invented new and Carburetors,of which the ollowing is a specification.

y invention relates to carbureters for in ternal combustion engines, andhas for its main object the provision of properly regulated proportionsof fuel and air to the engine through all degrees of rate of supplybetween the minimum and maximum limits of carburetor capacity. Otherobjects of my invention are the elimination of the mechanicalcomplications which accompany the use of springs, valves, and othersensitive moving parts, and the obtainment of etliciency and economy bythe aid of simple, structurally strong, and positively actuated movingparts.

The cardinal characteristics of my improved carburetor are: a box-likeconduit, with two opposite sides which approach each other from arelatively wide primary air inlet to a. point of minimum interior Widthof the conduit. and recede angularly from each other from said point ofminimum interior width toward the delivery end of the conduit. theelements of these double-trig pered sides being parallel with each o herin the direction at; right anu'les to the axis of the conduit. whichextends from the prithe delivery end; a piston member, fitting betweenthe, double tapered sides of the conduit and extending to a substantialdistance on either s de of the point of minimum interior width of thecoiiduit, and sliding between and in contact wfththc double taperedsides, in a direction at right angles with the axis of the conduit; alineally extended liquid fuel inlet which enters the conduit at or closeto the point of minimum width thereof, and which is controlled as toextent of opening by the movable piston member.

he piston member is mom'ited on and controlled by a rigidly connectedpiston rod, so that simple. positive connection with said rod or barsufiices to move the piston memher in the conduit, to increase ordecrease its capacity. The shape and extent of the conduit, and that ofthe piston member are such that at whatever position of the piston, the

cluit constitutes a regularly tapered duct,

Specification of Letters lfatent.

Patented Mar. 5, 1918. Serial No. 65,234.

of 'UGIMZ contradic form, of such extent inits axial direction that thesaid oena contracta form is not. interrupted or vitiated, and so thatthe stream of gaseous mixture components flows smoothly through theentire length of the conduit, Without eddy d1sturbance.

Preferably also, there is provided an auxiliary air inlet, lincallyextended in the dircction or the piston movement, in the side of theconduit and within the surface against which the piston makes slidinglit, and as near practicable to the end of the conduit, so as to disturband qualify as little as possible the regular "renacontracta shape ofthe conduit as a Whole.

The only necessary moving member of the carbureter is the piston-likemember above generally described. The air and fuel inlets will extend ina direction parallel or substantially so, with the movement of thepieton-like member, so that by movement of said member the exposed andeffective areas of the three inlets (two for air and one for fuel) aresimultaneously increased or diminished. The configuration of the mixingchamber or duct will be such, that its principal longitudinal section,2'. e. in the direction of flow of positions of the moving member. Thefuel inlet should, for the best effects, be placed between the primaryair inlet and the secondary or auxiliary air inlet and at the throat ornarrowest part of the conduit.

In the drawings hereto annexed, which exemplify in specific form theinvention more generally described abov'e,--

Figure 1 is a vertical cross; section of a earhureter;

Fig. 2 is an end elevation of the pistonlike member of the carburetor.

Fig. 3 is a horizontal section at the line Fig. l; and

Fig. 4 is a vertical longitudinal section through the mixture chamber orduet of the carburetor, showing the movable piston memben' in sideelevation.

The casing of the carburetor comprises float chamber A and the mixturechamher (I. A float, B, in the float chamber, is provided to control thesupply of volatile fuel in the usual manner.

The mixture chamber or duct C of a box, having a. cross section consistsof com fluids, is substantially uniform and unchanged In its essentialcontour at all contractor form, the sides of the box being parallel tothe direction of movement of the iston member I). This box is open atthe ottom at F, and communicates at the top with a conduit 1-1, whichleads to the en me.

*itting between the sides of the box 0 and extending from the air inletto the delivery end thereof, the movable piston member D is mounted toslide back and forth in the box C. The piston member D thus conforms incontour and extent to the longitudinal section of the box, (if. c.section in the direction of flow) or mixture duct C. To enable thepiston member D to slide smoothly without chattering or sticking, it isprovided with an extension D which acts like the cross head of a pistonrod, sliding on the inner surfaces of the mixture duct or box 0, as onslideways. A bar D, provided with rack teeth D, is secured to the pistonmember D, and may be actuated by means of a toothed segment E andcontrol rod E. The primary air inlet is at F, the secondary or auxiliaryair inlet is at I. The latter is a slot or aperture in one o the sidesof the box C The fuel inlet consists of a number of individual ducts G,each of which communicates with the liquid volatile fuel in the floatchamber A. The apertures of these ducts lie in a line preferably in theplane of minimum cross sectional area of the mixture conduit, so as tobe subjected to a maximum inductive influence by the stream of airflowing throu h the mixture duct C.

The operation of t e carburetor above de scribed is as follows: Theextension '1') of i the piston D, when the piston is at its extremefiosition of closure, servesto close the i e against ingress of anygas. The initial movement (to the left as viewed in Fig; 4) of thepiston member D simultane ously unmasks one of the liquid fuel inlets G,and.an initial area of the primary air mary air inlet F, more and morethe fuel inlets G, and also (after the first stage of opening is passed)more and more of the secondary or auxiliary air inlet I.

of the piston member D. carbureters of this character, under practicalIn the carbnreter shown in the drawings, the sides of the primary andsecondary air inlet apertures are parallel, and the fuel apertures G areall of the same size, so that the three inlet areas increase or diminishin direct arithmetical ratio with the movement l ixperimcnt with engineconditions, has led to the adoption by me of this preservation of directratio as, on the whole, productive of the best results Possibly underconditions outside of my personal experience, it may be found advisableto change these ratios by changing the shape of the three inlets, or of.some or more of them. It will be observed, that variation in capacity ofthe mixture duct takes place without. substantial variation in the sha eof the duct in the direction of flow. n effective contour being adopted,the beneficial results therefrom persist through all variations incapacity.

I claim:

1. In a carbureter, a conduit having sides the elements of which areparalleltin a direction transverse to its axis, and tapering to a throatfrom the air inlet end and mixture delivery end, forming a duct ofregularly tapered 'vena contracto form, a

iston member substantially corresponding in contour and extent to thechtire oena coniraczfiaconduit, and movable transversely to the axis ofsaid conduit, the conduit provided with a fuel inlet at the throat,lineally extended in the direction of movement of the piston member.

2. In a carbureter, a conduit having sides the elements of which. arearallel in a direction transverse to its axis, and tapering to a throatfrom the air inlet end and mixture delivery end, forming a duct ofregularly tapered oe'na contracta form, a piston member substantiallycorresponding in contour and extent to the entire 'vena contmctaconduit, and movable transversely

